This amended application for renewed funding of the Columbia University Skin Diseases Research Core Center Grant (SDRC) requests support for the purpose of sustaining and building a focus of excellence in cutaneous biology at Columbia University that will leverage the considerable existing research strength within the Department of Dermatology and harness it to the rich opportunities for collaborative research with talented investigators throughout the institution and the New York region. The theme of this project is: "Normal and Abnormal Growth of the Skin: From Stem Cells to Skin Cancer." The epidermis is the outermost layer of human skin and is a major body environmental interface. Physical and chemical insults lead to the acquisition of potentially oncogenic mutations in epidermal cells most of which are lost through differentiation, and only long-term epidermal residents, such as stem cells, accumulate the number of genetics essential for tumor development. This paradigm will provide the conceptual underpinning for this application. It is anticipated that the research supported by this SDRC will lead to improved diagnostic and therapeutic approaches to the management of skin cancer and other dermatologic diseases. It is our belief that this thematic approach has outstanding potential to link basic science advances to a better understanding of the mechanisms of human skin disease thereby offering real promise for finding innovative strategies for the prevention and treatment of these disorders. This proposal is supported by highly innovative cutting edge Core facilities designed to provide investigators with state-of-the-art support services for their research that would be difficult, if not impossible, to access elsewhere. These include: A) Skin Phenotyping Core; B) Cell and Tissue Kinetics Core; C) Molecular Biology Core; and D) Administrative Core. These highly interactive Cores are crucial for the closely linked Pilot and Feasibility (P&F) Study Program that provides a solid base on which to launch a more powerful presence in cutaneous biology at this institution. A major goal of this SDRC is to nurture the development of innovative ideas from investigators in the broader Columbia community that can ultimately be translated into peer-reviewed funded programs. In the prior application, the Reviewers expressed concern about "the low rating for 2 of the 4 P/F studies, with only one of the P/F projects receiving an outstanding rating." Another suggestion by the Reviewers was a more detailed cost-recovery mechanism for the operation of the Cores within this SDRC. These concerns have been thoroughly addressed in this revised application. We have made a concerted effort to obtain stronger P&F proposals. These were solicited from all Dermatology departments in the New York area and from the Columbia University faculty. After rigorous review, five of the twelve submitted were selected for this SDRC application, representing a mix of both new and senior investigators from outside the Department of Dermatology. The Cores and P&F Studies are integrated under the direction of an Administrative Core that provides highly effective and well-organized support to assure maximally efficient integration of the SDRC and its multiple components within Columbia University. A multifaceted enrichment program containing a broad spectrum of innovative educational activities is an integral component of this SDRC as is a major commitment to training outstanding medical students, residents, fellows and graduate students with real potential for future leadership in Dermatology a specialty with a need for strengthening its academic base. The Columbia University SDRC will build a base of excellence in cutaneous biology and investigative dermatology in the New York region that has the potential to enhance public and professional awareness of the importance of skin diseases and to improve the quality of life of individuals suffering from skin disease.